The present invention relates to a connecting device, consisting of an attachment head and a clamping device for connecting horizontal or diagonal scaffolding elements to the perforated discs of the vertical post elements, said attachment head having a bearing surface on one side by which means it is supported on the pipe of the post element, and a horizontal slit corresponding at least to the thickness of the perforated disc is present on the same side, said slit dividing the bearing surface into two sub-surfaces, and on which means for welding on a scaffolding pipe are provided on the side opposite the bearing surface.
Connecting devices of this type are known for example from DE-PS-24 49 124. Said reference describes a connection device for horizontal and/or diagonal scaffolding elements with vertical post elements. Said vertical post elements have regularly spaced holding means for suspending the horizontal and/or diagonal scaffolding elements, said holding means being provided with elongated holes in two directions being perpendicular to each other. The horizontal and/or diagonal scaffolding elements carry connecting devices on their ends, each consisting of an attachment head and a wedge. The attachment head has a slit corresponding at least to the thickness of the holding means, which in its built-in state extends perpendicular relative to the central axis of the vertical post element and which in its mounted state embraces said holding means.
The attachment heads of the horizontal and/or vertical scaffolding elements can be clamped tightly to the holding means by a wedge. By this design of the holes an exact alignment of the horizontal or diagonal scaffolding element can be achieved in straight-line as well as in right-angled direction without the use of special measuring methods.
This connecting device has proved itself to be valuable throughout many years. Said connecting device has the disadvantage that the bending moment that can be taken up by this connecting device is limited, so that the scaffolding may twist under high loads. Said disadvantage could be eliminated, by enlarging the attachment head that is situated on both ends of the horizontal or diagonal scaffolding elements, but which would also raise the weight of the bearing bar, making the handling of said bearing bar more difficult.
The object of the present invention is therefore, to provide a connecting device that can take up a higher bending moment than connecting devices according to the prior art without noticeably raising the weight of said connecting devices.
According to the present invention said object is achieved by providing a connecting device, consisting of an attachment head and a clamping device for connecting the horizontal or diagonal scaffolding elements to the perforated discs of the vertical post elements, whereby
the attachment head has a bearing surface on one side by which means said attachment head is supported on the pipe of the post element,
a horizontal slit corresponding at least to the thickness of the perforated disc is present on the same side, dividing the bearing surface into two sub-surfaces,
on the attachment head means for welding on a scaffolding pipe are provided on the side opposite the bearing surface,
the overall height of the attachment head on the side by which means said attachment head is supported on the pipe of the post element is at least 68 mm and
the top and bottom surface of the attachment head taper continuously from the bearing surface to the means for welding on a scaffolding pipe.
Preferably the top surface of the attachment head tapers along a curve that is made up of several convex and/or concave segments of a circle with different radius, whereas the bottom surface of the attachment head tapers along a convex segment of a circle with a constant radius.
Preferably the overall height of the attachment head on the side by which means said attachment head is supported on the pipe of the post element is 70 to 80 mm. In another preferred embodiment the ratio of the height of the upper sub-surface of the bearing surface to the height of the lower sub-surface of the bearing surface is 1:1.3 to 1:1.6.
The lateral boundary surfaces of the attachment head according to the present invention are preferably designed in such a way that they extend towards a center in a wedge-like manner. Particularly preferred said lateral boundary surfaces each form an angle of 22.5xc2x0, preferably 22xc2x0 or less, relative to the central axis.
On the side opposite the bearing surface the means for welding on the scaffolding pipe is situated, which preferably has a welding area suitable for welding as well as centering aids for the scaffolding pipes. Said welding area can be designed for round, rectangular or quadratic scaffolding pipes. By means of the centering aids the scaffolding pipe and the attachment head are centered relative to one another. Particularly for welding on round scaffolding pipes, 4 centering aids, displaced by 90xc2x0, relative to one another, are mounted on the attachment head, such that the difference between the outer surface of two centering aids, facing one another, is equal to or a little bit smaller than the inner diameter of the scaffolding pipe, which is directed via the centering aid prior to welding. For rectangular scaffolding pipes said centering aid is U-shaped.
If the attachment head is welded to a round scaffolding pipe, said welding area preferably has a ring-shaped connection surface, on which the round scaffolding tube is supported. The outer diameter of the ring-shaped connection surface is smaller than the outer diameter of the scaffolding tube. A cone-shaped surface having an outer diameter that is equal to or insignificantly bigger than the outer diameter of the scaffolding pipe is connected to the ring-shaped connection surface. A cyclindrical surface having a diameter that is equal to or insignificantly bigger than the outer diameter of the scaffolding pipe is connected to the cone-shaped surface. By this design of the welding area exactly defined welding conditions in the shape of half a Y-seam can be achieved, so that the welding connection can be made using a welding apparatus.
In another preferred embodiment the clamping device of the connecting device is a wedge. Said wedge is put through one of the holes of the holding means of the vertical post elements and is then secured, for example, with a hammer, so that a form-closed and non-positive connection between the horizontal or diagonal scaffolding elements and the vertical post elements results.
In another preferred embodiment, the attachment head additionally has preferably round or star-shaped bolts for non-positive connection with the overlying elements that are situated on the bearing bar. Preferably these bolts are situated on the left and right exterior surface of the attachment head. Said bolts are each flattened and integrated into the attachment head in such a way that the respective exterior surface of the bolts does not protrude the respective exterior surface of the attachment head. The bolts are preferably integrated into the mold for the production of the connecting device.
Another object of the present invention is a bearing bar consisting of a pipe and a connecting device according to the present invention on each of its two ends.
Another object of the present invention is the use of the connecting device according to the present invention and the use of the bearing bar according to the present invention as part of scaffolding system.